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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: ByteReader.html 842 2015-03-07 18:20:42Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.util;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>/**<a name="line.10"></a>
<span class="sourceLineNo">011</span> * Reads bytes from a buffer.<a name="line.11"></a>
<span class="sourceLineNo">012</span> */<a name="line.12"></a>
<span class="sourceLineNo">013</span>public class ByteReader {<a name="line.13"></a>
<span class="sourceLineNo">014</span><a name="line.14"></a>
<span class="sourceLineNo">015</span>    final byte[] buf;<a name="line.15"></a>
<span class="sourceLineNo">016</span>    final int max;<a name="line.16"></a>
<span class="sourceLineNo">017</span>    int off;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>    /**<a name="line.19"></a>
<span class="sourceLineNo">020</span>     * Constructor. The provided array is read from directly; no copy is made.<a name="line.20"></a>
<span class="sourceLineNo">021</span>     *<a name="line.21"></a>
<span class="sourceLineNo">022</span>     * @param buf array to read from<a name="line.22"></a>
<span class="sourceLineNo">023</span>     * @throws NullPointerException if {@code buf} is null<a name="line.23"></a>
<span class="sourceLineNo">024</span>     */<a name="line.24"></a>
<span class="sourceLineNo">025</span>    public ByteReader(byte[] buf) {<a name="line.25"></a>
<span class="sourceLineNo">026</span>        this.buf = buf;<a name="line.26"></a>
<span class="sourceLineNo">027</span>        this.max = buf.length;<a name="line.27"></a>
<span class="sourceLineNo">028</span>        this.off = 0;<a name="line.28"></a>
<span class="sourceLineNo">029</span>    }<a name="line.29"></a>
<span class="sourceLineNo">030</span><a name="line.30"></a>
<span class="sourceLineNo">031</span>    /**<a name="line.31"></a>
<span class="sourceLineNo">032</span>     * Constructor. The provided array is read from directly; no copy is made.<a name="line.32"></a>
<span class="sourceLineNo">033</span>     *<a name="line.33"></a>
<span class="sourceLineNo">034</span>     * @param buf array to read from<a name="line.34"></a>
<span class="sourceLineNo">035</span>     * @param off starting offset into {@code buf}<a name="line.35"></a>
<span class="sourceLineNo">036</span>     * @throws IndexOutOfBoundsException if {@code off} is out of bounds<a name="line.36"></a>
<span class="sourceLineNo">037</span>     * @throws NullPointerException if {@code buf} is null<a name="line.37"></a>
<span class="sourceLineNo">038</span>     */<a name="line.38"></a>
<span class="sourceLineNo">039</span>    public ByteReader(byte[] buf, int off) {<a name="line.39"></a>
<span class="sourceLineNo">040</span>        this(buf, off, buf.length - off);<a name="line.40"></a>
<span class="sourceLineNo">041</span>    }<a name="line.41"></a>
<span class="sourceLineNo">042</span><a name="line.42"></a>
<span class="sourceLineNo">043</span>    /**<a name="line.43"></a>
<span class="sourceLineNo">044</span>     * Constructor. The provided array is read from directly; no copy is made.<a name="line.44"></a>
<span class="sourceLineNo">045</span>     *<a name="line.45"></a>
<span class="sourceLineNo">046</span>     * @param buf array to read from<a name="line.46"></a>
<span class="sourceLineNo">047</span>     * @param off offset into {@code buf}<a name="line.47"></a>
<span class="sourceLineNo">048</span>     * @param len number of bytes to read<a name="line.48"></a>
<span class="sourceLineNo">049</span>     * @throws IndexOutOfBoundsException if {@code off} or {@code len} are out of bounds<a name="line.49"></a>
<span class="sourceLineNo">050</span>     * @throws NullPointerException if {@code buf} is null<a name="line.50"></a>
<span class="sourceLineNo">051</span>     */<a name="line.51"></a>
<span class="sourceLineNo">052</span>    public ByteReader(byte[] buf, int off, int len) {<a name="line.52"></a>
<span class="sourceLineNo">053</span>        if (off &lt; 0 || len &lt; 0 || off &gt; buf.length || off + len &lt; 0 || off + len &gt; buf.length)<a name="line.53"></a>
<span class="sourceLineNo">054</span>            throw new IndexOutOfBoundsException("buf.length = " + buf.length + ", off = " + off + ", len = " + len);<a name="line.54"></a>
<span class="sourceLineNo">055</span>        this.buf = buf;<a name="line.55"></a>
<span class="sourceLineNo">056</span>        this.max = off + len;<a name="line.56"></a>
<span class="sourceLineNo">057</span>        this.off = off;<a name="line.57"></a>
<span class="sourceLineNo">058</span>    }<a name="line.58"></a>
<span class="sourceLineNo">059</span><a name="line.59"></a>
<span class="sourceLineNo">060</span>    /**<a name="line.60"></a>
<span class="sourceLineNo">061</span>     * Constructor. Takes a snapshot of the given writer's entire content.<a name="line.61"></a>
<span class="sourceLineNo">062</span>     *<a name="line.62"></a>
<span class="sourceLineNo">063</span>     * @param writer {@code ByteWriter} to read data from<a name="line.63"></a>
<span class="sourceLineNo">064</span>     * @throws NullPointerException if {@code writer} is null<a name="line.64"></a>
<span class="sourceLineNo">065</span>     */<a name="line.65"></a>
<span class="sourceLineNo">066</span>    public ByteReader(ByteWriter writer) {<a name="line.66"></a>
<span class="sourceLineNo">067</span>        this(writer.buf, 0, writer.len);<a name="line.67"></a>
<span class="sourceLineNo">068</span>    }<a name="line.68"></a>
<span class="sourceLineNo">069</span><a name="line.69"></a>
<span class="sourceLineNo">070</span>    /**<a name="line.70"></a>
<span class="sourceLineNo">071</span>     * Constructor. Takes a snapshot of the given writer's content starting at the specified position.<a name="line.71"></a>
<span class="sourceLineNo">072</span>     *<a name="line.72"></a>
<span class="sourceLineNo">073</span>     * @param writer {@code ByteWriter} to read data from<a name="line.73"></a>
<span class="sourceLineNo">074</span>     * @param mark position previously returned by {@code ByteWriter#mark}<a name="line.74"></a>
<span class="sourceLineNo">075</span>     * @throws IndexOutOfBoundsException if {@code mark} is out of bounds<a name="line.75"></a>
<span class="sourceLineNo">076</span>     * @throws NullPointerException if {@code writer} is null<a name="line.76"></a>
<span class="sourceLineNo">077</span>     */<a name="line.77"></a>
<span class="sourceLineNo">078</span>    public ByteReader(ByteWriter writer, int mark) {<a name="line.78"></a>
<span class="sourceLineNo">079</span>        this(writer.buf, mark, writer.len - mark);<a name="line.79"></a>
<span class="sourceLineNo">080</span>    }<a name="line.80"></a>
<span class="sourceLineNo">081</span><a name="line.81"></a>
<span class="sourceLineNo">082</span>    /**<a name="line.82"></a>
<span class="sourceLineNo">083</span>     * Peek at next byte, if any.<a name="line.83"></a>
<span class="sourceLineNo">084</span>     *<a name="line.84"></a>
<span class="sourceLineNo">085</span>     * @return next byte (0-255)<a name="line.85"></a>
<span class="sourceLineNo">086</span>     * @throws IndexOutOfBoundsException if there are no more bytes<a name="line.86"></a>
<span class="sourceLineNo">087</span>     */<a name="line.87"></a>
<span class="sourceLineNo">088</span>    public int peek() {<a name="line.88"></a>
<span class="sourceLineNo">089</span>        if (this.off == this.max)<a name="line.89"></a>
<span class="sourceLineNo">090</span>            throw new IndexOutOfBoundsException();<a name="line.90"></a>
<span class="sourceLineNo">091</span>        return this.buf[this.off] &amp; 0xff;<a name="line.91"></a>
<span class="sourceLineNo">092</span>    }<a name="line.92"></a>
<span class="sourceLineNo">093</span><a name="line.93"></a>
<span class="sourceLineNo">094</span>    /**<a name="line.94"></a>
<span class="sourceLineNo">095</span>     * Read the next byte.<a name="line.95"></a>
<span class="sourceLineNo">096</span>     *<a name="line.96"></a>
<span class="sourceLineNo">097</span>     * @return next byte (0-255)<a name="line.97"></a>
<span class="sourceLineNo">098</span>     * @throws IndexOutOfBoundsException if there are no more bytes<a name="line.98"></a>
<span class="sourceLineNo">099</span>     */<a name="line.99"></a>
<span class="sourceLineNo">100</span>    public int readByte() {<a name="line.100"></a>
<span class="sourceLineNo">101</span>        if (this.off == this.max)<a name="line.101"></a>
<span class="sourceLineNo">102</span>            throw new IndexOutOfBoundsException();<a name="line.102"></a>
<span class="sourceLineNo">103</span>        return this.buf[this.off++] &amp; 0xff;<a name="line.103"></a>
<span class="sourceLineNo">104</span>    }<a name="line.104"></a>
<span class="sourceLineNo">105</span><a name="line.105"></a>
<span class="sourceLineNo">106</span>    /**<a name="line.106"></a>
<span class="sourceLineNo">107</span>     * Unread the previously read byte. Equivalent to {@code unread(1)}.<a name="line.107"></a>
<span class="sourceLineNo">108</span>     *<a name="line.108"></a>
<span class="sourceLineNo">109</span>     * @throws IndexOutOfBoundsException if there are no more bytes to unread<a name="line.109"></a>
<span class="sourceLineNo">110</span>     */<a name="line.110"></a>
<span class="sourceLineNo">111</span>    public void unread() {<a name="line.111"></a>
<span class="sourceLineNo">112</span>        if (this.off == 0)<a name="line.112"></a>
<span class="sourceLineNo">113</span>            throw new IndexOutOfBoundsException();<a name="line.113"></a>
<span class="sourceLineNo">114</span>        this.off--;<a name="line.114"></a>
<span class="sourceLineNo">115</span>    }<a name="line.115"></a>
<span class="sourceLineNo">116</span><a name="line.116"></a>
<span class="sourceLineNo">117</span>    /**<a name="line.117"></a>
<span class="sourceLineNo">118</span>     * Unread the given number of previously read bytes.<a name="line.118"></a>
<span class="sourceLineNo">119</span>     *<a name="line.119"></a>
<span class="sourceLineNo">120</span>     * @param len the number of bytes to unread<a name="line.120"></a>
<span class="sourceLineNo">121</span>     * @throws IndexOutOfBoundsException if there are no more bytes to unread<a name="line.121"></a>
<span class="sourceLineNo">122</span>     */<a name="line.122"></a>
<span class="sourceLineNo">123</span>    public void unread(int len) {<a name="line.123"></a>
<span class="sourceLineNo">124</span>        if (this.off - len &lt; 0)<a name="line.124"></a>
<span class="sourceLineNo">125</span>            throw new IndexOutOfBoundsException();<a name="line.125"></a>
<span class="sourceLineNo">126</span>        this.off -= len;<a name="line.126"></a>
<span class="sourceLineNo">127</span>    }<a name="line.127"></a>
<span class="sourceLineNo">128</span><a name="line.128"></a>
<span class="sourceLineNo">129</span>    /**<a name="line.129"></a>
<span class="sourceLineNo">130</span>     * Read the specified number of bytes.<a name="line.130"></a>
<span class="sourceLineNo">131</span>     *<a name="line.131"></a>
<span class="sourceLineNo">132</span>     * @param len number of bytes to read<a name="line.132"></a>
<span class="sourceLineNo">133</span>     * @return bytes read<a name="line.133"></a>
<span class="sourceLineNo">134</span>     * @throws IndexOutOfBoundsException if there are not enough bytes<a name="line.134"></a>
<span class="sourceLineNo">135</span>     * @throws IllegalArgumentException if {@code len} is negative<a name="line.135"></a>
<span class="sourceLineNo">136</span>     */<a name="line.136"></a>
<span class="sourceLineNo">137</span>    public byte[] readBytes(int len) {<a name="line.137"></a>
<span class="sourceLineNo">138</span>        if (len &lt; 0)<a name="line.138"></a>
<span class="sourceLineNo">139</span>            throw new IllegalArgumentException("len &lt; 0");<a name="line.139"></a>
<span class="sourceLineNo">140</span>        if (this.off + len &gt; this.max)<a name="line.140"></a>
<span class="sourceLineNo">141</span>            throw new IndexOutOfBoundsException();<a name="line.141"></a>
<span class="sourceLineNo">142</span>        final byte[] result = new byte[len];<a name="line.142"></a>
<span class="sourceLineNo">143</span>        System.arraycopy(this.buf, this.off, result, 0, len);<a name="line.143"></a>
<span class="sourceLineNo">144</span>        this.off += len;<a name="line.144"></a>
<span class="sourceLineNo">145</span>        return result;<a name="line.145"></a>
<span class="sourceLineNo">146</span>    }<a name="line.146"></a>
<span class="sourceLineNo">147</span><a name="line.147"></a>
<span class="sourceLineNo">148</span>    /**<a name="line.148"></a>
<span class="sourceLineNo">149</span>     * Get the number of bytes remaining.<a name="line.149"></a>
<span class="sourceLineNo">150</span>     *<a name="line.150"></a>
<span class="sourceLineNo">151</span>     * @return bytes remaining<a name="line.151"></a>
<span class="sourceLineNo">152</span>     */<a name="line.152"></a>
<span class="sourceLineNo">153</span>    public int remain() {<a name="line.153"></a>
<span class="sourceLineNo">154</span>        return this.max - this.off;<a name="line.154"></a>
<span class="sourceLineNo">155</span>    }<a name="line.155"></a>
<span class="sourceLineNo">156</span><a name="line.156"></a>
<span class="sourceLineNo">157</span>    /**<a name="line.157"></a>
<span class="sourceLineNo">158</span>     * Skip over bytes.<a name="line.158"></a>
<span class="sourceLineNo">159</span>     *<a name="line.159"></a>
<span class="sourceLineNo">160</span>     * @param num the number of bytes to skip<a name="line.160"></a>
<span class="sourceLineNo">161</span>     * @throws IndexOutOfBoundsException if {@code num} is negative<a name="line.161"></a>
<span class="sourceLineNo">162</span>     * @throws IndexOutOfBoundsException if less than {@code num} bytes remain<a name="line.162"></a>
<span class="sourceLineNo">163</span>     */<a name="line.163"></a>
<span class="sourceLineNo">164</span>    public void skip(int num) {<a name="line.164"></a>
<span class="sourceLineNo">165</span>        if (num &lt; 0 || this.off + num &gt; this.max)<a name="line.165"></a>
<span class="sourceLineNo">166</span>            throw new IndexOutOfBoundsException();<a name="line.166"></a>
<span class="sourceLineNo">167</span>        this.off += num;<a name="line.167"></a>
<span class="sourceLineNo">168</span>    }<a name="line.168"></a>
<span class="sourceLineNo">169</span><a name="line.169"></a>
<span class="sourceLineNo">170</span>    /**<a name="line.170"></a>
<span class="sourceLineNo">171</span>     * Get current offset into buffer.<a name="line.171"></a>
<span class="sourceLineNo">172</span>     *<a name="line.172"></a>
<span class="sourceLineNo">173</span>     * @return current offset<a name="line.173"></a>
<span class="sourceLineNo">174</span>     */<a name="line.174"></a>
<span class="sourceLineNo">175</span>    public int getOffset() {<a name="line.175"></a>
<span class="sourceLineNo">176</span>        return this.off;<a name="line.176"></a>
<span class="sourceLineNo">177</span>    }<a name="line.177"></a>
<span class="sourceLineNo">178</span><a name="line.178"></a>
<span class="sourceLineNo">179</span>    /**<a name="line.179"></a>
<span class="sourceLineNo">180</span>     * Get maximum offset into buffer.<a name="line.180"></a>
<span class="sourceLineNo">181</span>     *<a name="line.181"></a>
<span class="sourceLineNo">182</span>     * @return maximum offset<a name="line.182"></a>
<span class="sourceLineNo">183</span>     */<a name="line.183"></a>
<span class="sourceLineNo">184</span>    public int getMax() {<a name="line.184"></a>
<span class="sourceLineNo">185</span>        return this.max;<a name="line.185"></a>
<span class="sourceLineNo">186</span>    }<a name="line.186"></a>
<span class="sourceLineNo">187</span><a name="line.187"></a>
<span class="sourceLineNo">188</span>    /**<a name="line.188"></a>
<span class="sourceLineNo">189</span>     * Copy a range of bytes from the buffer. Does not change the read position.<a name="line.189"></a>
<span class="sourceLineNo">190</span>     *<a name="line.190"></a>
<span class="sourceLineNo">191</span>     * @param off offset into buffer<a name="line.191"></a>
<span class="sourceLineNo">192</span>     * @param len number of bytes<a name="line.192"></a>
<span class="sourceLineNo">193</span>     * @return copy of the specified byte range<a name="line.193"></a>
<span class="sourceLineNo">194</span>     * @throws IndexOutOfBoundsException if {@code off} and/or {@code len} is out of bounds<a name="line.194"></a>
<span class="sourceLineNo">195</span>     */<a name="line.195"></a>
<span class="sourceLineNo">196</span>    public byte[] getBytes(int off, int len) {<a name="line.196"></a>
<span class="sourceLineNo">197</span>        final byte[] data = new byte[len];<a name="line.197"></a>
<span class="sourceLineNo">198</span>        System.arraycopy(this.buf, off, data, 0, len);<a name="line.198"></a>
<span class="sourceLineNo">199</span>        return data;<a name="line.199"></a>
<span class="sourceLineNo">200</span>    }<a name="line.200"></a>
<span class="sourceLineNo">201</span><a name="line.201"></a>
<span class="sourceLineNo">202</span>    /**<a name="line.202"></a>
<span class="sourceLineNo">203</span>     * Copy a range of bytes from the given offset to the end of the buffer. Does not change the read position.<a name="line.203"></a>
<span class="sourceLineNo">204</span>     *<a name="line.204"></a>
<span class="sourceLineNo">205</span>     * @param off offset into buffer<a name="line.205"></a>
<span class="sourceLineNo">206</span>     * @return copy of the specified byte range<a name="line.206"></a>
<span class="sourceLineNo">207</span>     * @throws IndexOutOfBoundsException if {@code off} is out of bounds<a name="line.207"></a>
<span class="sourceLineNo">208</span>     */<a name="line.208"></a>
<span class="sourceLineNo">209</span>    public byte[] getBytes(int off) {<a name="line.209"></a>
<span class="sourceLineNo">210</span>        return this.getBytes(off, this.max - off);<a name="line.210"></a>
<span class="sourceLineNo">211</span>    }<a name="line.211"></a>
<span class="sourceLineNo">212</span><a name="line.212"></a>
<span class="sourceLineNo">213</span>    /**<a name="line.213"></a>
<span class="sourceLineNo">214</span>     * Copy all the of bytes in the buffer. Does not change the read position.<a name="line.214"></a>
<span class="sourceLineNo">215</span>     *<a name="line.215"></a>
<span class="sourceLineNo">216</span>     * @return copy of the entire buffer<a name="line.216"></a>
<span class="sourceLineNo">217</span>     */<a name="line.217"></a>
<span class="sourceLineNo">218</span>    public byte[] getBytes() {<a name="line.218"></a>
<span class="sourceLineNo">219</span>        return this.max == this.buf.length ? this.buf.clone() : this.getBytes(0);<a name="line.219"></a>
<span class="sourceLineNo">220</span>    }<a name="line.220"></a>
<span class="sourceLineNo">221</span><a name="line.221"></a>
<span class="sourceLineNo">222</span>    /**<a name="line.222"></a>
<span class="sourceLineNo">223</span>     * Mark current read position.<a name="line.223"></a>
<span class="sourceLineNo">224</span>     *<a name="line.224"></a>
<span class="sourceLineNo">225</span>     * @return the current offset<a name="line.225"></a>
<span class="sourceLineNo">226</span>     */<a name="line.226"></a>
<span class="sourceLineNo">227</span>    public int mark() {<a name="line.227"></a>
<span class="sourceLineNo">228</span>        return this.off;<a name="line.228"></a>
<span class="sourceLineNo">229</span>    }<a name="line.229"></a>
<span class="sourceLineNo">230</span><a name="line.230"></a>
<span class="sourceLineNo">231</span>    /**<a name="line.231"></a>
<span class="sourceLineNo">232</span>     * Reset read position to a previously marked position.<a name="line.232"></a>
<span class="sourceLineNo">233</span>     *<a name="line.233"></a>
<span class="sourceLineNo">234</span>     * @param mark value previously returned by {@link #mark}<a name="line.234"></a>
<span class="sourceLineNo">235</span>     * @throws IndexOutOfBoundsException if {@code mark} is out of bounds<a name="line.235"></a>
<span class="sourceLineNo">236</span>     */<a name="line.236"></a>
<span class="sourceLineNo">237</span>    public void reset(int mark) {<a name="line.237"></a>
<span class="sourceLineNo">238</span>        if (mark &lt; 0 || mark &gt; this.max)<a name="line.238"></a>
<span class="sourceLineNo">239</span>            throw new IndexOutOfBoundsException();<a name="line.239"></a>
<span class="sourceLineNo">240</span>        this.off = mark;<a name="line.240"></a>
<span class="sourceLineNo">241</span>    }<a name="line.241"></a>
<span class="sourceLineNo">242</span>}<a name="line.242"></a>
<span class="sourceLineNo">243</span><a name="line.243"></a>




























































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